feat(contracts): add infrastructure-maintenance contract

New responsibility contract consolidating host-level system maintenance
and Docker image lifecycle management, filling the gap left by
infrastructure-update (which owns cluster-wide apt waves).

Scope:
- OS package updates on primary host with pre-update snapshot/backup check
- Docker image pulls for LiteLLM, SearXNG, and other running containers
- Container restarts with per-stack health verification
- Post-update verification: LiteLLM, SearXNG, Zulip, Gitea, PM2, Hermes gateways
- Rollback on failure (image/apt/config restore) with circuit breaker

Owner: ops (firstmate secondmate). Trigger: weekly Sunday 2am ET.
Escalation: warning/critical->abiba+mumuni, fatal->abiba+mumuni+kwame.
circuit_breaker: max_retries 2, window 7200, trip_action escalate_to_fatal.
depends_on: infrastructure-monitoring (pre-update health baseline).

Registry:
- Add infrastructure-maintenance to by_category.maintenance, by_domain.infrastructure,
  by_owner.ops (new), by_trigger.scheduled, by_sensitivity.high
- Add 'ops' to owners list
- Move infrastructure-update owner abiba -> ops (in contracts entry + by_owner index)

Also adds '## Maintaining this file' section to AGENTS.md per fm-ensure-agents-md.

contract-registry.yaml

@@ -22,6 +22,7 @@ owners:
 - abiba
 - mumuni
 - kwame
+- ops
 trigger_types:
 - scheduled
 - event_driven
@@ -58,6 +59,7 @@ index:
     - memory-audit-maintenance
     - gpu-fleet
     - infrastructure-update
+    - infrastructure-maintenance
     reference:
     - infrastructure-control
     - ra-h-os-custodianship-contract
@@ -90,6 +92,7 @@ index:
     - infrastructure-control
     - infrastructure-monitoring
     - infrastructure-update
+    - infrastructure-maintenance
     - pm2-self-heal
     - disk-gc-threat-response
     gpu:
@@ -130,7 +133,6 @@ index:
     - build-zulip-plugin
     - stirling-pdf-agent-access
     - gpu-fleet
-    - infrastructure-update
     - infrastructure-control
     - zulip-adapter-lessons
     - pi-approval-architecture
@@ -144,6 +146,9 @@ index:
     - mumuni-delegation
     kwame:
     - hello-world
+    ops:
+    - infrastructure-maintenance
+    - infrastructure-update
   by_trigger:
     scheduled:
     - hermes-key-enforcement
@@ -156,6 +161,7 @@ index:
     - litellm-health
     - memory-audit-maintenance
     - infrastructure-update
+    - infrastructure-maintenance
     event_driven:
     - litellm-self-heal
     - pm2-self-heal
@@ -197,6 +203,7 @@ index:
     - hermes-zulip-plugin
     - build-zulip-plugin
     - infrastructure-update
+    - infrastructure-maintenance
     - ra-h-os-custodianship-contract
     - mumuni-delegation
     normal:
@@ -1256,13 +1263,108 @@ contracts:
   last_run: null
   last_status: null
   drift_alerts: []
+- name: infrastructure-maintenance
+  file: infrastructure-maintenance.prose.md
+  kind: responsibility
+  category: maintenance
+  sensitivity: high
+  status: active
+  owner: ops
+  version: 1.0.0
+  trigger:
+    type: scheduled
+    cadence: 0 2 * * 0
+    description: Weekly host-level maintenance Sunday at 2am ET (replaces infrastructure-update
+      build-phase role; infra-update moves to ops)
+    cron_job_id: null
+  execution:
+    agent: ops
+    timeout: 3600
+    requires:
+    - infrastructure-monitoring run within last 30 minutes (pre-update health baseline)
+    - Proxmox snapshot of primary host OR /tmp backup dir created this run
+    - LiteLLM master key from Infisical vault for health verification
+    protocol:
+    - Load contract from prose-contracts/main
+    - Phase 0 preflight — capture health baseline, backup check, record image baseline
+    - Phase 1 apt update && apt upgrade -y on primary host
+    - Phase 2 docker compose pull for LiteLLM, SearXNG, and other running containers
+    - Phase 3 restart stacks one at a time with per-stack health verification
+    - Phase 4 verify every critical service (LiteLLM, SearXNG, Zulip, Gitea, PM2, Hermes gateways)
+    - On failure — rollback per protocol, escalate, do not loop beyond circuit breaker
+    - Log actions to ~/.hermes/runs/infrastructure-maintenance/
+  verification:
+    postconditions:
+    - check: all critical services running after update
+      verify: 'curl -sf http://192.168.68.116/litellm/v1/models && curl -sf https://chat.sysloggh.net/api/v1/server_settings && curl -sf https://git.sysloggh.net/api/v1/version && curl -sf http://192.168.68.7:8888 && pm2 jlist'
+      expect: all probes 200 OK / processes online
+    - check: no regressions from pre-update health baseline
+      verify: diff Phase 0 health-baseline against Phase 4 results
+      expect: no GREEN service turned RED
+    - check: docker containers on latest stable tags
+      verify: docker inspect --format '{{.Config.Image}}' <container> per service matches image-baseline.pulled_tag
+      expect: all containers running pulled tags
+    - check: APT packages up to date with no held broken packages
+      verify: apt list --upgradable 2>/dev/null | wc -l and apt-get -s upgrade | grep -ci broken
+      expect: upgradable == 0, broken == 0
+    artifact: maintenance run report with phase results and any rollback/escalation
+    verify_commands:
+    - curl -sf http://192.168.68.116/litellm/v1/models
+    - curl -sf http://192.168.68.7:8888
+    - curl -sf https://chat.sysloggh.net/api/v1/server_settings
+    - curl -sf https://git.sysloggh.net/api/v1/version
+    - pm2 jlist
+  receipt:
+    format: json
+    storage: ~/.hermes/runs/infrastructure-maintenance/
+    graph_node: true
+    schema:
+      contract: string
+      run_id: string
+      timestamp: ISO 8601
+      agent: string
+      status: pass|fail|escalated
+      phase: preflight|apt|images|restarts|verify|rollback|done|failed
+      actions_taken: array
+      postconditions: array
+      drift_alerts: array
+      evidence_path: string
+  escalation:
+    info:
+      action: log_to_receipt
+      notify: []
+    warning:
+      action: relay_alert
+      notify:
+      - abiba
+      - mumuni
+    critical:
+      action: relay_alert
+      notify:
+      - abiba
+      - mumuni
+    fatal:
+      action: relay_alert + pause + human_required
+      notify:
+      - abiba
+      - mumuni
+      - kwame
+  circuit_breaker:
+    max_retries: 2
+    window: 7200
+    trip_action: escalate_to_fatal
+  depends_on:
+  - infrastructure-monitoring
+  last_run: null
+  last_status: null
+  drift_alerts: []
 - name: infrastructure-update
   file: infrastructure-update.prose.md
   kind: responsibility
   category: maintenance
   sensitivity: high
   status: active
-  owner: abiba
+  owner: ops
   version: 1.0.0
   trigger:
     type: scheduled